School of BioSciences - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 17
-
ItemNo Preview AvailableEconomic costs of biological invasions in the United Kingdom(PENSOFT PUBLISHERS, 2021-07-29)Although the high costs of invasion are frequently cited and are a key motivation for environmental management and policy, synthesised data on invasion costs are scarce. Here, we quantify and examine the monetary costs of biological invasions in the United Kingdom (UK) using a global synthesis of reported invasion costs. Invasive alien species have cost the UK economy between US$6.9 billion and $17.6 billion (£5.4 – £13.7 billion) in reported losses and expenses since 1976. Most costs were reported for the entire UK or Great Britain (97%); country-scale cost reporting for the UK's four constituent countries was scarce. Reports of animal invasions were the costliest ($4.7 billion), then plant ($1.3 billion) and fungal ($206.7 million) invasions. Reported damage costs (i.e. excluding management costs) were higher in terrestrial ($4.8 billion) than aquatic or semi-aquatic environments ($29.8 million), and primarily impacted agriculture ($4.2 billion). Invaders with earlier introduction years accrued significantly higher total invasion costs. Invasion costs have been increasing rapidly since 1976, and have cost the UK economy $157.1 million (£122.1 million) per annum, on average. Published information on specific economic costs included only 42 of 520 invaders reported in the UK and was generally available only for the most intensively studied taxa, with just four species contributing 90% of species-specific costs. Given that many of the invasive species lacking cost data are actively managed and have well-recognised impacts, this suggests that cost information is incomplete and that totals presented here are vast underestimates owing to knowledge gaps. Financial expenditure on managing invasions is a fraction (37%) of the costs incurred through damage from invaders; greater investments in UK invasive species research and management are, therefore, urgently required.
-
ItemNo Preview AvailableFour priority areas to advance invasion science in the face of rapid environmental change(CANADIAN SCIENCE PUBLISHING, 2021-06)Unprecedented rates of introduction and spread of non-native species pose burgeoning challenges to biodiversity, natural resource management, regional economies, and human health. Current biosecurity efforts are failing to keep pace with globalization, revealing critical gaps in our understanding and response to invasions. Here, we identify four priority areas to advance invasion science in the face of rapid global environmental change. First, invasion science should strive to develop a more comprehensive framework for predicting how the behavior, abundance, and interspecific interactions of non-native species vary in relation to conditions in receiving environments and how these factors govern the ecological impacts of invasion. A second priority is to understand the potential synergistic effects of multiple co-occurring stressors— particularly involving climate change—on the establishment and impact of non-native species. Climate adaptation and mitigation strategies will need to consider the possible consequences of promoting non-native species, and appropriate management responses to non-native species will need to be developed. The third priority is to address the taxonomic impediment. The ability to detect and evaluate invasion risks is compromised by a growing deficit in taxonomic expertise, which cannot be adequately compensated by new molecular technologies alone. Management of biosecurity risks will become increasingly challenging unless academia, industry, and governments train and employ new personnel in taxonomy and systematics. Fourth, we recommend that internationally cooperative biosecurity strategies consider the bridgehead effects of global dispersal networks, in which organisms tend to invade new regions from locations where they have already established. Cooperation among countries to eradicate or control species established in bridgehead regions should yield greater benefit than independent attempts by individual countries to exclude these species from arriving and establishing.
-
ItemNo Preview AvailableGlobal economic costs of aquatic invasive alien species(ELSEVIER, 2021-06-25)Much research effort has been invested in understanding ecological impacts of invasive alien species (IAS) across ecosystems and taxonomic groups, but empirical studies about economic effects lack synthesis. Using a comprehensive global database, we determine patterns and trends in economic costs of aquatic IAS by examining: (i) the distribution of these costs across taxa, geographic regions and cost types; (ii) the temporal dynamics of global costs; and (iii) knowledge gaps, especially compared to terrestrial IAS. Based on the costs recorded from the existing literature, the global cost of aquatic IAS conservatively summed to US$345 billion, with the majority attributed to invertebrates (62%), followed by vertebrates (28%), then plants (6%). The largest costs were reported in North America (48%) and Asia (13%), and were principally a result of resource damages (74%); only 6% of recorded costs were from management. The magnitude and number of reported costs were highest in the United States of America and for semi-aquatic taxa. Many countries and known aquatic alien species had no reported costs, especially in Africa and Asia. Accordingly, a network analysis revealed limited connectivity among countries, indicating disparate cost reporting. Aquatic IAS costs have increased in recent decades by several orders of magnitude, reaching at least US$23 billion in 2020. Costs are likely considerably underrepresented compared to terrestrial IAS; only 5% of reported costs were from aquatic species, despite 26% of known invaders being aquatic. Additionally, only 1% of aquatic invasion costs were from marine species. Costs of aquatic IAS are thus substantial, but likely underreported. Costs have increased over time and are expected to continue rising with future invasions. We urge increased and improved cost reporting by managers, practitioners and researchers to reduce knowledge gaps. Few costs are proactive investments; increased management spending is urgently needed to prevent and limit current and future aquatic IAS damages.
-
ItemPropagule availability drives post-wildfire recovery of peatland plant communities(WILEY, 2021-07)QUESTION: Northern peatlands are increasingly threatened by wildfire. Severe peatland wildfires can provide opportunities for new non‐peatland species to colonise post fire. Changes in plant colonisation could lead to longer‐term shifts in community composition, compromising recovery of peatland structure and function. Understanding the process of post‐fire recovery can thus inform restoration action and help restore peatland vascular plant communities. In this study, we ask: what drives initial vascular plant recovery following a peatland wildfire? LOCATION: Stalybridge moors, England (commonly referred to as the Saddleworth moors). METHODS: We used a series of vegetation surveys and seed germination experiments to identify the composition of vascular plant community one‐year post fire, along with potential propagule sources. We combined this with plant trait data and, using a series of null models, compared observed community trait values against random species assemblages. RESULTS: Our data suggests that plant species are able to arrive at the burned site through multiple non‐exclusive recolonisation pathways. This includes colonisation through the soil seed bank, along with dispersal from surrounding unburned peatland and non‐peatland vegetation. The composition and structure of the recolonised communities was largely determined by the ability of species to reach the post‐fire site from these donor communities. This resulted in a post‐fire community composed of species possessing lower seed masses relative to the wider pool of potential colonisers. CONCLUSIONS: Our results highlight propagule availability as a driver of post‐wildfire vascular plant recovery. This provides opportunities for new non‐peatland species to colonise, potentially driving changes in the direction of vegetation recovery. Ensuring the availability of peatland species following a wildfire could therefore be key to the immediate recovery of these systems.
-
Item
-
ItemApplying the stress-gradient hypothesis to curb the spread of invasive bamboo(WILEY, 2021-09)Abstract The stress‐gradient hypothesis (SGH) provides a conceptual framework for explaining how environmental context determines the nature of biotic interactions. It may be also useful for predicting geographic variability in the effect of management interventions on biological invasions. We aimed to test hypotheses consistent with the SGH to explain context dependency in bamboo invasion of secondary forests in Japan, and establish a predictive understanding of forest management impacts on invasion. We use a priori physiological knowledge of invasive giant bamboo,Phyllostachys bambusoides, to generate hypotheses consistent with the SGH. We modelled variation in giant bamboo occupancy within 810 secondary forest plots across the broad environmental gradients of Japan using a national vegetation database. Consistent with the SGH, we find that the effect of tree canopy cover on bamboo occupancy depends on interactions between solar radiation and mean annual temperature. In cool regions with high solar radiation—stressful conditions for bamboo—shade cast by dense canopies facilitates invasion. However, in warmer regions that are more benign, dense canopies tend to inhibit spread via competition for light, space and other resources. Synthesis and applications. We provide evidence that the stress‐gradient hypothesis can inform practical recommendations for invasive species control. We characterised geographic variability in the effect of forest thinning, a widespread management intervention used to enhance forest biodiversity, on the risk of bamboo spread into secondary forests in Japan. Thinning forest canopies to increase understorey light radiation should limit bamboo spread in cooler regions, while tree planting to increase canopy shade should limit bamboo spread in warmer regions.
-
ItemMechanistic reconciliation of community and invasion ecology(WILEY, 2021-02)Community and invasion ecology have mostly grown independently. There is substantial overlap in the processes captured by different models in the two fields, and various frameworks have been developed to reduce this redundancy and synthesize information content. Despite broad recognition that community and invasion ecology are interconnected, a process-based framework synthesizing models across these two fields is lacking. Here we review 65 representative community and invasion models and propose a common framework articulated around six processes (dispersal, drift, abiotic interactions, within-guild interactions, cross-guild interactions, and genetic changes). The framework is designed to synthesize the content of the two fields, provide a general perspective on their development, and enable their comparison. The application of this framework and of a novel method based on network theory reveals some lack of coherence between the two fields, despite some historical similarities. Community ecology models are characterized by combinations of multiple processes, likely reflecting the search for an overarching theory to explain community assembly and structure, drawing predominantly on interaction processes, but also accounting largely for the other processes. In contrast, most models in invasion ecology invoke fewer processes and focus more on interactions between introduced species and their novel biotic and abiotic environment. The historical dominance of interaction processes and their independent developments in the two fields is also reflected in the lower level of coherence for models involving interactions, compared to models involving dispersal, drift, and genetic changes. It appears that community ecology, with a longer history than invasion ecology, has transitioned from the search for single explanations for patterns observed in nature to investigate how processes may interact mechanistically, thereby generating and testing hypotheses. Our framework paves the way for a similar transition in invasion ecology, to better capture the dynamics of multiple alien species introduced in complex communities. Reciprocally, applying insights from invasion to community ecology will help us understand and predict the future of ecological communities in the Anthropocene, in which human activities are weakening species' natural boundaries. Ultimately, the successful integration of the two fields could advance a predictive ecology that is urgently required in a rapidly changing world.
-
ItemA conceptual map of invasion biology: Integrating hypotheses into a consensus network(WILEY, 2020-06)BACKGROUND AND AIMS: Since its emergence in the mid-20th century, invasion biology has matured into a productive research field addressing questions of fundamental and applied importance. Not only has the number of empirical studies increased through time, but also has the number of competing, overlapping and, in some cases, contradictory hypotheses about biological invasions. To make these contradictions and redundancies explicit, and to gain insight into the field's current theoretical structure, we developed and applied a Delphi approach to create a consensus network of 39 existing invasion hypotheses. RESULTS: The resulting network was analysed with a link-clustering algorithm that revealed five concept clusters (resource availability, biotic interaction, propagule, trait and Darwin's clusters) representing complementary areas in the theory of invasion biology. The network also displays hypotheses that link two or more clusters, called connecting hypotheses, which are important in determining network structure. The network indicates hypotheses that are logically linked either positively (77 connections of support) or negatively (that is, they contradict each other; 6 connections). SIGNIFICANCE: The network visually synthesizes how invasion biology's predominant hypotheses are conceptually related to each other, and thus, reveals an emergent structure - a conceptual map - that can serve as a navigation tool for scholars, practitioners and students, both inside and outside of the field of invasion biology, and guide the development of a more coherent foundation of theory. Additionally, the outlined approach can be more widely applied to create a conceptual map for the larger fields of ecology and biogeography.
-
ItemGlobal gene flow releases invasive plants from environmental constraints on genetic diversity(NATL ACAD SCIENCES, 2020-02-25)When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.
-
ItemRestored river-floodplain connectivity promotes woody plant establishment(ELSEVIER, 2021-08-01)Riparian forest ecosystems are declining globally. Many floodplains no longer flood and thus cease to satisfy the hydrologic requirements for riparian tree maintenance and regeneration. To promote woody riparian plant recruitment where flood regimes have been altered by flow regulation, effective approaches to restoration need to be developed. We implemented a landscape-scale experiment in a remnant, temperate floodplain forest. By constructing two weirs within channelized reaches of a stream, we redirected flows into networks of historic distributary channels, which facilitated widespread floodplain inundation. Using a control-reference-impact study design, we assessed the establishment and growth of planted seedlings of three woody species (Eucalyptus camphora, Leptospermum lanigerum and Melaleuca squarrosa) over 13 months in response to flooding achieved by floodplain reconnection. Planted seedlings had higher height and diameter growth rates at both induced (19–29 cm, 1 mm) and naturally flooded (34–44 cm, 3–5 mm) than at non-flooded (4–10 cm, −5 to −3 mm) sites. However, survival rates and temporal growth patterns differed between species according to variation in flood duration and soil moisture, illustrating the different hydrological requirements of the coexisting species. This highlights that variable flooding and drying patterns are essential to create recruitment niches for different riparian plant species and shows the importance of river-floodplain connectivity for providing adequate flooding regimes. Our study demonstrates the suitability of two complementary restoration approaches – restoring hydrology and active revegetation – for promoting the regeneration of riparian forests.